JP5214335B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device used in a communication system that requires a small and wide-band antenna device.

  In various communication systems, small and wideband antennas are required based on demands for downsizing and high performance of devices. Examples of those that meet the demand for miniaturization include an inverted-F antenna and a patch antenna. The inverted F antenna can be antenna-matched even if it is lowered (downsized) by a metal pin that is short-circuited near the feeding point. However, there is a problem that the frequency band that can be matched is limited by a small loop passing through the feeding point and the metal pin. Therefore, in order to support a plurality of broadband wireless systems, an antenna height corresponding to the wireless system is required.

  The patch antenna is configured by disposing the radiation conductor and the conductor ground plane so as to face each other with an insulating material as an inclusion, and can be thinned (downsized). However, this patch antenna also has a problem that the operable band is narrow.

  On the other hand, as seen in Patent Document 1, an attempt has been made to widen the operable band by inserting a magnetic material into the patch antenna. However, the combination of the patch antenna and the magnetic material is not always sufficient for both miniaturization and wide band. Further, the resonance frequency is relatively high at 3.5 to 4.5 GHz.

In order to exhibit the effect of broadening the band by inserting the magnetic body into the antenna, a thickness of 10 μm or more, more specifically 100 μm or more is required. In addition, the dielectric characteristics of the magnetic material also affect the antenna characteristics, and it is necessary to have high insulation. However, at present, there is no thick insulating magnetic material having a high permeability in a high frequency band of 3.5 to 4.5 GHz, and having a thickness of 10 μm or more, more specifically 100 μm or more.
JP 2007-124696 A

  In the conventional antenna device, there is a problem that it is difficult to achieve both a reduction in size including a low profile and a wide band in a band of several hundred MHz to 5 GHz.

  The present invention has been made in consideration of the above-mentioned circumstances, and the object of the present invention is to make it possible to achieve both a reduction in size and a broadening of the bandwidth in a few hundred MHz to 5 GHz band, such as a cellular phone, etc. An object of the present invention is to provide a small antenna device that can be mounted on a small device.

An antenna device according to an aspect of the present invention includes a finite ground plane, a rectangular conductor plate that is provided above the finite ground plane, has one side connected to the finite ground plane, and includes a bent portion substantially parallel to the one side, and above the finite ground plane. The antenna is disposed substantially parallel to the finite ground plane, extends in a direction substantially perpendicular to the one side, and a feeding point is located in the vicinity of the other side facing the one side of the rectangular conductor plate, and the finite ground plane and the antenna At least a portion of the magnetic provided in the space member, have a, the magnetic material, Fe, Co, and a magnetic metal containing at least one selected from the group consisting of Ni, Mg, Al, Si between , Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr, and at least one element selected from carbon (C) and nitrogen (N) A core shell comprising: a magnetic metal particle comprising: an oxide coating layer that is coated on a surface of the magnetic metal particle and includes an oxide containing at least one nonmagnetic metal that is one of the components of the magnetic metal particle. and type magnetic particles comprises a void, the core-shell magnetic particles, characterized in that organic and an insulating material of a resin or an inorganic material dispersed.

An antenna device according to another aspect of the present invention includes a finite ground plane, a magnetic body above the finite ground plane, a rectangular conductor plate above the magnetic body, and a penetrating through the magnetic body. A conductor connected to the finite ground plane; and a conductor disposed above the finite ground plane in substantially parallel to the finite ground plane, extending in a direction substantially perpendicular to the one side, and having a feeding point facing the one side of the rectangular conductor plate possess an antenna located in the vicinity of the side, wherein the magnetic material, Fe, Co, and a magnetic metal containing at least one selected from the group consisting of Ni, Mg, Al, Si, Ca, Zr, Ti, Magnetic metal particles comprising at least one nonmagnetic metal selected from the group consisting of Hf, Zn, Mn, rare earth elements, Ba and Sr, and at least one element selected from carbon (C) and nitrogen (N); The magnetic metal particles Core-shell type magnetic particles that are coated on the surface of the core-shell magnetic material particles and include an oxide coating layer made of an oxide containing at least one non-magnetic metal that is one of the constituent components of the magnetic metal particles; type magnetic particles, characterized in that organic and an insulating material dispersed resin or an inorganic material.

An antenna device according to yet another aspect of the present invention is provided with a finite ground plane and above the finite ground plane, one end of which is connected on a predetermined straight line of the finite ground plane, bends at a substantially right angle, and is substantially parallel to the straight line. A comb-shaped linear conductor whose other end is substantially parallel to the straight line, and disposed substantially parallel to the finite ground plane above the finite ground plane, extending in a direction substantially perpendicular to the straight line, and having a feeding point an antenna located in the vicinity of the other end of the comb-shaped linear conductor, have a, a magnetic member provided on at least a portion of the space between said finite ground plane antenna, the magnetic body, Fe, A magnetic metal containing at least one selected from the group consisting of Co and Ni, and at least one selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr Non-magnetic metal and carbon (C And magnetic metal particles containing at least one element selected from nitrogen (N), and at least one nonmagnetic metal that is coated on the surface of the magnetic metal particles and is one of the constituent components of the magnetic metal particles a core-shell magnetic particles comprising an oxide coating layer formed of an oxide containing, with an air gap, the core-shell magnetic particles, characterized in that organic and an insulating material dispersed resin or an inorganic material .

  According to the present invention, in a band of several hundreds of MHz to 5 GHz, it is possible to achieve both a reduction in size including a low profile and a wider band, and it is possible to provide a small antenna device that can be mounted on a small device such as a mobile phone. It becomes.

  As described above, in the conventional antenna device, it has been difficult to achieve both a reduction in size and a reduction in bandwidth in a few hundred MHz to 5 GHz band. In order to solve this problem, the inventors have developed a new antenna structure and an insulating high-permeability thick-film magnetic body (not less than 10 μm) having a novel excellent magnetic property (high μ ′ and low μ ″). In other words, we have devised a combination of a thickness of 100 μm or more.

  Hexagonal ferrite is conceivable as a thick film magnetic body having a thickness of 10 μm or more, preferably 100 μm or more, which realizes a relatively high magnetic permeability in the band of several hundred MHz to 5 GHz. However, in a high frequency band of several hundred MHz or more, it approaches the ferromagnetic resonance frequency, and the magnetic loss due to resonance becomes remarkable and cannot be used.

  On the other hand, magnetic materials have been actively developed by thin film technology such as sputtering and plating, and it has been confirmed that the film exhibits excellent characteristics in the high frequency band at the thin film level. However, the characteristics with a thick film of 10 μm or more have not been confirmed, and there is a problem that enormous film formation time is required to increase the film thickness to 10 μm, or more than 100 μm. In addition, since these thin film magnetic bodies generally have low resistance, there is a problem that induced current is generated and antenna characteristics are adversely affected.

  In addition, thin film technology such as sputtering requires large equipment. Also, the controllability such as the film thickness is not always good. Therefore, the method is not always satisfactory in terms of cost and yield. As described below, the inventors have excellent high frequency magnetic characteristics, that is, a high permeability real part (μ ′) and a low permeability imaginary part (μ ″) in the high frequency band, and transmission loss. We have developed an insulating high-permeability thick-film magnetic body that suppresses as much as possible and applied it to the antenna device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
The antenna device according to the present embodiment includes a finite ground plane, a rectangular conductor plate provided above the finite ground plane, connected to the finite ground plane, and having a bent portion substantially parallel to the one side, and a finite ground plane above the finite ground plane. At least one between the finite ground plane and the antenna, which is disposed substantially in parallel, extends in a direction substantially perpendicular to the one side of the tip, and has a feeding point in the vicinity of the other side facing the tip of the rectangular conductor plate. And a magnetic body provided in the space of the part. Here, “upper” is an expression for indicating a positional relationship based on the case where the finite ground plane is below, and is not necessarily an expression indicating that it is always above the vertical direction. Further, the term “above” includes a case where two elements are in contact with each other.

  FIG. 1 is a configuration diagram of an antenna device according to a first embodiment of the present invention. 1A is a perspective view, FIG. 1B is a sectional view, and FIG. 1C is a sectional view of a modification.

  The antenna device includes a finite ground plane 10, a rectangular conductor plate 12 provided above the finite ground plane 10, an antenna 14 disposed substantially parallel to the finite ground plane 10 above the finite ground plane 10, and the finite ground plane 10 and the antenna 14. And a magnetic body 16 provided in at least a part of the space. In FIG. 1, a magnetic body 16 is inserted between the finite ground plane 10 and the rectangular conductor plate 12. In FIG. 1A, the magnetic body 16 is illustrated separately from the antenna device for easy understanding of the configuration of the antenna device.

  In FIG. 1B, a space is provided between the magnetic body 16 and the finite ground plane 10 and the rectangular conductor plate 12. However, in order to enhance the effect of inserting the magnetic body 16, it is more desirable to eliminate these spaces and bring the magnetic body 16 into contact with the finite ground plane 10 and the rectangular conductor plate 12. Further, in FIG. 1B, the magnetic body 16 is inserted only between the rectangular conductor plate 12 and the finite ground plane. However, as shown in FIG. 1C, the magnetic body 16 protrudes outside the rectangular conductor plate 12. The antenna 14 may be inserted into the antenna 14, or may be inserted between the antenna 14 and the rectangular conductor plate 12.

  However, from the viewpoint of adhesion between the magnetic body 16 and the finite ground plane 10, the rectangular conductor plate 12, and the antenna 14, it may be necessary to intervene other materials in the space between them. In such a case, the dielectric occupies the space between the finite ground plane 10 and the antenna 14 other than the space occupied by the magnetic material, and the dielectric and the magnetic material have the same refractive index. It is more preferable to select a combination of magnetic material.

  In the case of a magnetic material alone or a combination of a magnetic material and a dielectric material having different refractive indexes, reflection of radio waves occurs at the interface between the magnetic material and air, or the interface between the magnetic material and the dielectric material. This is because if there is a loss, the radiation efficiency of the antenna device is deteriorated, and if there is no loss, the band is narrowed. By making the refractive index of the space constant, unnecessary radio wave reflection can be suppressed, and deterioration of radiation efficiency can be suppressed. The above discussion also applies to FIGS. 3B, 3C, and 6.

  Both the finite ground plane 10 and the rectangular conductor plate 12 are made of a conductive material. One side of the rectangular conductor plate 12 is connected to the finite ground plane 10 and is electrically short-circuited. And the bending part 18 substantially parallel to this one side is provided. The antenna 14 is provided above the rectangular conductor plate 12, and the antenna 14 extends in a substantially vertical direction on one side where the rectangular conductor plate 12 is in contact with the finite ground plane 10. The feeding point 22 of the antenna 14 is located in the vicinity of the other side facing the one side of the rectangular conductor plate 12. In FIG. 1, the antenna 14 is a dipole antenna.

  The bent portion 18 of the rectangular conductor plate 12 may be formed by bending a rectangular conductor plate, or if electrically equivalent, two rectangular conductor plates may be prepared instead of being bent. May be physically and electrically connected by a method such as soldering. In the antenna device of FIG. 1, the bent portion 18 of the rectangular conductor plate 12 is a right angle, and is composed of a portion parallel to the finite ground plane 10 and a portion perpendicular to the finite ground plane 10. However, this structure is not essential, and it is not particularly necessary to have this structure as long as electromagnetic wave propagation under the rectangular conductor plate 10 can be obtained. That is, it is not always necessary to bend the rectangular conductor plate 12 at a right angle or to provide a portion parallel or perpendicular to the finite ground plane 10.

  Further, the fact that the feeding point 22 of the antenna 14 is located in the vicinity of the other side facing the one side of the rectangular conductor plate 12 means that the position of the feeding point 22 is 6 minutes from the other side of the electromagnetic wave having the operating frequency of the antenna 14. It means the range of 1 wavelength or less. The reason is that the position adjustment range of the feeding point 22 for antenna matching is within this range as described later.

  FIG. 1 illustrates the case where the antenna 14 is a dipole antenna. The dipole antenna of FIG. 1 arranges two linear conductors in a straight line and feeds power therebetween.

  FIG. 2 is a configuration diagram of a first modification of the antenna device according to the present embodiment. In this modification, a plate-shaped dipole antenna is applied as the antenna 14. The plate-shaped dipole antenna feeds the center where two conductor plates are lined up, and the dipole is processed obliquely so that the distance between the two conductor plates increases as the side closer to the feed point 22 moves away from the feed point One of the antenna variants. The plate-shaped dipole antenna has an advantage that a wider band characteristic can be realized than a dipole antenna using a linear conductor.

  FIG. 3 is a configuration diagram of a second modification of the antenna device according to the present embodiment. 3A is a perspective view, FIG. 3B is a cross-sectional view, and FIG. 3C is a further modification of the second modification. In this modification, a monopole antenna is applied as the antenna 14. The monopole antenna is an antenna in which the linear conductor far from the rectangular conductor plate 12 is removed from the dipole antenna of FIG. 1 and the feeding point 22 side is bent so that the feeding point 22 is on the finite ground plane 10. In order to realize further miniaturization of the antenna device, the monopole antenna is preferable to the dipole antenna.

  As shown in FIGS. 1A, 1B, 2, 3A, and 3B, the magnetic body 16 has at least a portion between the antenna 14 and the rectangular conductor plate 12, for example, a rectangular shape. It is inserted between the conductor plate 12 and the finite ground plane 10.

  With the above configuration, the antenna device according to the present embodiment can achieve impedance matching even when the antenna device is downsized, including low profile, and can obtain wideband characteristics. This action and effect of the present embodiment will be described in detail below.

  FIG. 4 is an explanatory diagram of the operating principle when no magnetic material is inserted in the antenna device of the present embodiment. 4A shows a case where the antenna exists in free space, FIG. 4B shows a case where the antenna is located above the finite ground plane, and FIG. 4C shows a case where the antenna has a rectangular conductor plate.

As shown in FIG. 4A, assuming a current J flowing on the dipole antenna 14 in free space, a voltage V ₀ is generated at the feeding point by the electric field generated by the current J. The input impedance Z ₀ = V ₀ / J of the dipole antenna 14 is obtained from the current J and the voltage V ₀ . In the case of a half-wave dipole antenna, it is known to be about 72Ω.

  FIG. 4B shows a case where the dipole antenna 14 is arranged in parallel to the finite ground plane 10 above the finite ground plane 10. Here, there are two electric fields generated by the current J: an electric field A generated on the semi-infinite free space above the dipole antenna 14 and an electric field B generated by being reflected by the finite ground plane 10 below the dipole antenna 14. It is done.

The impedance when the dipole antenna 14 is lowered is different depending on the reflection phase φ at the point of reflection. In the case of a PEC (Perfect Electric Conductor) whose characteristics of the reflector are close to those of metal, φ = 180 degrees, and a voltage is generated when the position of the reflector is lowered to the limit, that is, the antenna is close to the limit. The input impedance is zero. Reflector PMC; becomes the phi = 0 degrees when the (Perfect Magnetic Conductor complete magnetic conductor), twice the voltage of the free space in the limit of low-profile is generated, the input impedance becomes 2Z _0.

If φ = 120 degrees = 2π / 3 rad,
exp (jωt) + exp {j (ωt ± 2π / 3)} = exp {j (ωt ± π / 3)}
The input impedance is Z ₀ which is the same as that in free space.

  The lower part of FIG. 4B is a diagram showing the relationship between the reflection phase and the voltage with a phasor. A phasor represents a change in an alternating current signal as a vector on a complex plane, and an actual voltage amplitude can be found by looking at a real part or an imaginary part of the phasor. In the lower left figure, the phasor of the electric field generated by the path A electromagnetic wave and the phasor of the electric field generated by the path B reflected by the PEC cancel each other with a phase difference of 180 degrees. The second figure from the lower left shows that in-phase reflection occurs in the PMC and doubles the voltage. The third figure from the lower left shows that reflection of a 120 degree phase difference does not change the amplitude of the voltage.

  FIG.4 (c) is sectional drawing of the state which does not insert the magnetic body of the antenna device of this Embodiment. Since the rectangular conductor plate 12 is short-circuited to the finite ground plane 10, it resonates at a frequency at which the shortest distance from the short-circuit point to the open end is about a quarter wavelength. At the resonance frequency of the rectangular conductor plate 12, the electromagnetic wave in the path propagating under the rectangular conductor plate 12 as indicated by B1 in FIG. 4C is dominant in terms of power. At this time, if the rectangular conductor plate 12 has a sufficiently low posture, a portion of the path B1 that passes under the rectangular conductor plate 12 has a substantially half wavelength in a reciprocating manner. That is, the phase changes by approximately 180 degrees while reciprocating under the rectangular conductor plate 2.

  Further, since a reflection phase of 180 degrees is generated in a portion perpendicular to the finite ground plane 10 of the rectangular conductor plate 12, a phase difference of approximately 360 degrees = 0 degrees is required before entering the path B1 under the rectangular conductor plate 12 and then exiting. Will occur. This corresponds to the PMC described above. Furthermore, if the position of the feeding point of the antenna is separated from the tip of the rectangular conductor plate 12 by about 1/6 wavelength, a phase difference of 120 degrees can be obtained in addition to the phase difference of 360 degrees = 0 degrees.

  In this way, a phase difference of 360 degrees is obtained by separating the rectangular conductor plate 12 from the tip of the rectangular conductor plate 12 and the dipole antenna 14 by 360 degrees. As described above, it is possible to obtain an input impedance equivalent to that in free space.

  The lower part of FIG. 4C is a diagram showing the relationship between the reflection phase and the voltage with a phasor. When the power of the electromagnetic wave propagation path B1 due to the resonance of the rectangular conductor plate 12 is dominant, but the short-range reflection B2 from the upper surface of the finite ground plane 10 or the rectangular conductor plate 12 cannot be ignored, FIG. As shown in the lower diagram, if the feeding point of the dipole antenna 14 is brought close to the tip of the rectangular conductor plate 12 so as to shift the reflection phase of the path B1 to the 0 degree side, the combined wave of the paths B1 and B2 has a phase difference of 120. Can be degrees.

  The space below the rectangular conductor plate 12 can be regarded as a parallel plate line. Therefore, as the width is increased, superposition of propagation in an oblique angle direction (hereinafter referred to as a propagation mode) is more likely to be excited, and the change in amplitude with respect to frequency varies for each propagation mode. For this reason, it is easy to increase the bandwidth of the antenna device.

  FIG. 5 is a cross-sectional view of an antenna device when a monopole antenna is used. Similar to the description of the operating principle when the dipole antenna is used, the rectangular conductor plate 12 resonates at a specific frequency. At that frequency, the electromagnetic wave in the path B1 that passes under the rectangular conductor plate 12 and reflects at a phase of 120 degrees is dominant, so the input impedance of the monopole antenna 14 is just below the monopole antenna 14 of the finite ground plane 10. It is almost the same as the input impedance when there is no portion. That is, the input impedance is equivalent to that in free space.

  Further, even when the power of the electromagnetic wave of the path B2 directly reflected at a short distance from the upper surface of the finite ground plane 10 or the rectangular conductor plate 12 directly below the monopole antenna 14 cannot be ignored, the feeding point of the monopole antenna 14 is set to the rectangular conductor. When approaching the open end of the plate 12, the combined wave of the paths B1 and B2 can be set to a phase difference of 120 degrees, as in the case of the dipole antenna.

  As described above, by providing the antenna device with the rectangular conductor plate, it is possible to obtain the antenna matching by obtaining the input impedance equivalent to the free space even in a low posture. Furthermore, this rectangular conductor plate is linearly short-circuited on one side of the rectangular conductor plate with respect to the finite ground plane. With this structure, the rectangular conductor plate can have current path distributions of various lengths such as a current in a path oblique to the rectangular conductor plate or a current in the shortest path in the short-circuit direction. Accordingly, a 120-degree reflection phase can be maintained in a wide frequency band, and the antenna device can be widened.

  Furthermore, in the present embodiment, a further reduction in size and bandwidth can be achieved by inserting a magnetic material into at least a part of the space between the antenna and the finite ground plane. This is because the wavelength shortening effect is generated by the dielectric constant and permeability of the magnetic material, the resonance frequency is lowered, and the antenna can be downsized. Moreover, it is because it becomes possible to widen the band by the magnetic permeability of the magnetic material.

  FIG. 3C is a further modification of the second modification of the present embodiment. As in the magnetic bodies 16a, 16b, and 16c shown in this figure, the magnetic body is inserted or arranged in as much space as possible between and around the antenna 14 and the finite ground plane 10 to further reduce the size and increase the bandwidth. From the viewpoint of. 1, 2, and 3, a space is provided between the magnetic body 16 and the finite ground plane 10, the rectangular conductor plate 12, and the antenna 14. However, in order to enhance the effect of inserting the magnetic body 16, it is more desirable to eliminate these spaces and bring the magnetic body 16 into contact with the finite ground plane 10, the rectangular conductor plate 12, and the antenna 14.

  However, from the viewpoint of adhesion between the magnetic body 16 and the finite ground plane 10, the rectangular conductor plate 12, and the antenna 14, it may be necessary to intervene other materials in the space between them. In such a case, the dielectric occupies the space between the finite ground plane 10 and the antenna 14 other than the space occupied by the magnetic material, and the dielectric and the magnetic material have the same refractive index. It is more preferable to select a combination of magnetic material.

  In the case of a magnetic substance alone or a combination of a magnetic substance and a dielectric substance with different refractive indexes, radio wave reflection occurs at the interface between the magnetic substance and air, or the interface between the magnetic substance and dielectric, and the radiation efficiency of the antenna device This is because it causes deterioration. By making the refractive index of the space constant, unnecessary radio wave reflection can be suppressed, and deterioration of radiation efficiency can be suppressed.

  In order to reduce the size and bandwidth of the antenna device, the magnetic material to be inserted is preferably a thick film of 10 μm or more, more preferably 100 μm or more. Moreover, in order to suppress the loss due to the induced current, it is desirable that the resistance of the magnetic material is large, and it is desirable to have a resistance value comparable to that of a general oxide.

  Next, the magnetic material used in this embodiment will be described in detail. First, the configuration of the magnetic material will be described. The magnetic body of the present embodiment includes core-shell magnetic particles and an insulating material having voids in which the particles are dispersed. Note that the magnetic body having this configuration is desirable for downsizing and widening the antenna device, but the present embodiment is not necessarily limited to the configuration of the magnetic body.

  It is desirable that the core-shell magnetic particles have a filling rate (volume ratio) of 10 vol% or more and 70 vol% or less with respect to the entire magnetic material. When the filling rate exceeds 70 vol%, the electrical resistance of the magnetic material is reduced, eddy current loss increases, and high-frequency magnetic characteristics may be deteriorated. If the filling rate is less than 10 vol%, the filling rate of the magnetic metal is lowered, so that the saturation magnetization of the magnetic material is lowered, and there is a possibility that the permeability is lowered.

  Further, it is desirable that the insulating material occupies a filling rate of 5 vol% or more and 80 vol% or less in the magnetic body. If it is less than 5 vol%, the particles cannot be bound to each other and the strength of the magnetic member may be reduced. If it exceeds 80 vol%, the volume ratio of the core-shell magnetic particles in the entire magnetic member is lowered, and the magnetic permeability may be lowered.

Examples of the insulating material include a resin and an inorganic material. The resin is not particularly limited, but polyester resin, polyethylene resin, polystyrene resin, polyvinyl chloride resin, polyvinyl butyral resin, polyurethane resin, cellulose resin, ABS resin, nitrile-butadiene rubber, styrene-butadiene resin Rubber, epoxy resin, phenol resin, amide resin, imide resin, fluorine resin, or a copolymer thereof is used. Inorganic materials are ceramics, glass, etc., such as an oxide, nitride, and carbide. Specifically, the inorganic material is an oxide containing at least one metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr, AlN, Si ₃ N ₄ , SiC and the like can be mentioned.

  The method of integrating the core-shell type magnetic particles into a sheet is not particularly limited, but for example, the core-shell type magnetic particles, a resin, and a solvent can be mixed to form a slurry, which can be applied and dried. Alternatively, the mixture of core-shell magnetic particles and resin may be pressed and molded into a sheet or pellet. Further, the core-shell magnetic particles may be dispersed in a solvent and deposited by a method such as electrophoresis.

  For example, the magnetic body may be a laminated magnetic body formed of a magnetic layer and a nonmagnetic dielectric layer. By simply laminating the non-magnetic dielectric layers without simply laminating the magnetic layers, it is possible to cut off the magnetic coupling and reduce the influence of the total demagnetizing field in the bulk. In other words, by interposing a nonmagnetic dielectric layer between the magnetic layers, it is possible to cut off the magnetic coupling between the magnetic layers and reduce the size of the magnetic poles to reduce the influence of the demagnetizing field. become. Furthermore, since the thickness of the magnetic material layer can be substantially increased, it is possible to improve the magnetic characteristics (permeability × thickness) in the bulk total.

  As described above, after forming a magnetic layer containing core-shell magnetic particles into a sheet shape having a thickness of 100 μm or less, and laminating the sheet-like magnetic material layer alternately with a nonmagnetic dielectric layer having a thickness of 100 μm or less, By having a laminated structure obtained by pressure bonding, heating, and sintering, the high-frequency magnetic characteristics of the magnetic material are improved.

  The magnetic permeability and dielectric constant of the magnetic material are determined by the components of the magnetic material, that is, the core-shell magnetic particles, the insulating material, and the filling rate. The permeability and permittivity that can realize low loss at several hundred MHz to several GHz are both greater than 1 and 10 or less.

  Here, when a magnetic material is incorporated in the antenna device, the size of the antenna tends to be small in proportion to the square root of the product of the magnetic permeability and dielectric constant of the magnetic material. Also, the degree of widening of the antenna tends to be roughly proportional to the square root of the magnetic permeability of the magnetic material and roughly inversely proportional to the square root of the dielectric constant.

  Therefore, when the magnetic permeability and the dielectric constant are greater than 1 and 10 or less, the product of the dielectric constant and the magnetic permeability can be increased, so that the wavelength shortening effect is great and the contribution to downsizing is increased. In addition, the bandwidth can be increased by the effect of magnetic permeability as compared with the case of using a dielectric alone. More preferably, the magnetic permeability is larger than the dielectric constant.

  For example, when core-shell type magnetic particles are used, it is possible to synthesize two types of cases where the magnetic permeability is greater than 1 and less than or equal to 5 and the magnetic permeability is greater than the dielectric constant and smaller. When the former magnetic permeability is larger than the dielectric constant, the contribution to the broadening of the antenna becomes large. At this time, since the product of the dielectric constant and the magnetic permeability is not so large, the wavelength shortening effect is not so great, and the contribution to miniaturization is not so great. Of course, the size can be reduced as compared with the case of using a dielectric alone. On the other hand, if the magnetic permeability of the latter is smaller than the dielectric constant, the contribution to the broadening of the antenna is not so great (of course, the broadening of the bandwidth is possible compared to the case of the dielectric alone), but the wavelength shortening effect is Greatly contributes to downsizing.

  From the above, it is required to comprehensively judge the demands for downsizing and widening the band, and to select the magnetic permeability and dielectric constant of the magnetic material. As described above, this can be easily controlled by the constituents of the magnetic material, that is, the core-shell type magnetic particles and the insulating material and the filling rate.

  Next, the core-shell type magnetic particle that is one of the components of the magnetic material will be described. The core-shell magnetic particle includes a core of magnetic metal particles that are metal nanoparticles, and a shell of an oxide coating layer that is coated on the surface of the magnetic metal particles. The magnetic metal particles include a magnetic metal containing at least one selected from the group consisting of Fe, Co, Ni, Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba, and At least one nonmagnetic metal selected from the group consisting of Sr and at least one element selected from carbon and nitrogen. The oxide coating layer is preferably made of an oxide containing at least one nonmagnetic metal that is one of the constituent components of the magnetic metal particles. Here, the oxide may be a composite oxide containing two or more kinds of metals.

  The magnetic metal contained in the magnetic metal particles contains at least one selected from the group consisting of Fe, Co, and Ni, and is particularly preferable because an Fe-based alloy, a Co-based alloy, and an FeCo-based alloy can achieve high saturation magnetization. The Fe-based alloy contains Ni, Mn, Cu or the like as the second component, and examples thereof include FeNi alloy, FeMn alloy, and FeCu alloy. Examples of the Co-based alloy include Ni, Mn, Cu, and the like as the second component, such as a CoNi alloy, a CoMn alloy, and a CoCu alloy. Examples of the FeCo-based alloy include alloys containing Ni, Mn, Cu and the like as the second component. These second components are effective components for improving the high-frequency magnetic properties of the core-shell magnetic particles.

  Among magnetic metals, it is particularly preferable to use an FeCo-based alloy. The amount of Co in FeCo is preferably 10 atomic% or more and 50 atomic% or less from the viewpoint of satisfying thermal stability, oxidation resistance and high saturation magnetization. A more preferable amount of Co in FeCo is in the range of 20 atomic% to 40 atomic% from the viewpoint of further increasing saturation magnetization.

  The magnetic metal particles preferably contain a nonmagnetic metal. The nonmagnetic metal contained in the magnetic metal particles is at least one nonmagnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr. . These non-magnetic metals are elements that have a small standard Gibbs energy of oxide formation and are easily oxidized, and are preferable from the viewpoint of improving the insulating stability of the oxide coating layer that is a shell that covers the core of the magnetic metal particles. It is an element. In other words, a metal having a large standard generation Gibbs energy is not preferable because it is difficult to become an oxide.

  In addition, since the oxide coating layer of the shell is an oxide or composite oxide containing one or more nonmagnetic metals that are one of the components of the magnetic metal particles of the core, the magnetic metal particles and the oxide of the shell Adhesiveness and bondability with the coating layer are improved, and the material is thermally stable. Among these, Al and Si are preferable because they are easily dissolved in Fe, Co, and Ni, which are the main components of the magnetic metal particles, and contribute to the improvement of the thermal stability of the core-shell magnetic particles. In particular, the use of Al is preferable because the thermal stability and oxidation resistance are increased. A complex oxide containing a plurality of types of nonmagnetic metals also includes a solid solution form.

  The oxide coating layer preferably has a thickness of 0.1 nm to 100 nm, more preferably 0.1 nm to 20 nm. When the thickness of the oxide coating layer is less than 0.1 nm, the oxidation resistance becomes insufficient and the core-shell type magnetic particles covered with the oxide coating layer are integrated to produce a desired member. , The eddy current loss is likely to occur, and the high frequency characteristics of the magnetic permeability may be deteriorated. On the other hand, when the thickness of the oxide coating layer exceeds 100 nm, the core-shell type magnetic particles covered with the oxide coating layer are integrated to produce a desired member. There is a possibility that the filling rate of the magnetic metal particles contained in the material will be reduced, resulting in a decrease in the saturation magnetization of the member and a decrease in the magnetic permeability.

  The magnetic metal particles preferably contain carbon and nitrogen, either alone or in combination. When at least one of carbon and nitrogen is dissolved in the magnetic metal, the magnetic anisotropy of the core-shell magnetic particles can be increased. A magnetic material containing such core-shell magnetic particles having a large magnetic anisotropy can increase the ferromagnetic resonance frequency, and is a material suitable for use in a high frequency band. That is, the imaginary part of magnetic permeability (μ ″) in the high frequency band can be reduced, and therefore, it is suitable for use in the high frequency band.

  The magnetic metal particles preferably contain a nonmagnetic metal and at least one element selected from carbon and nitrogen, in addition to the magnetic metal, in amounts of 0.001 atomic% to 20 atomic%, respectively. If the content of the nonmagnetic metal and at least one element selected from carbon and nitrogen exceeds 20 atomic%, the saturation magnetization of the magnetic particles may be reduced. Further, if it is less than 0.001 atomic%, there is a possibility that the effect of maintaining good magnetic anisotropy, thermal stability and oxidation resistance may not be obtained.

  In particular, in magnetic metal particles containing a FeCo-based alloy as a magnetic metal, Al as a non-magnetic metal, and carbon (C) as the above-mentioned element, Al is 0.001 atomic% or more and 5 atoms relative to the FeCo-based alloy. % Or less, more preferably 0.01 atomic% or more and 5 atomic% or less, and carbon is 0.001 atomic% or more and 5 atomic% or less, more preferably 0.01 atomic% or more and 5 atomic% or less with respect to the FeCo-based alloy. It is desirable to blend in a range. When the magnetic metal is an FeCo-based alloy and Al and carbon are contained in the range of 0.001 atomic% to 5 atomic%, respectively, it becomes possible to maintain particularly good magnetic anisotropy and saturation magnetization, Magnetic permeability at higher frequencies can be increased.

  It is preferable that at least two of elements such as magnetic metal, nonmagnetic metal, carbon, and nitrogen contained in the magnetic metal particles are in solid solution with each other. By solid solution, magnetic anisotropy can be effectively improved, so that high-frequency magnetic characteristics can be improved. In addition, the mechanical properties of the core-shell magnetic particles can be improved. That is, if segregated at the grain boundaries or surfaces of the magnetic metal particles without being dissolved, it may be difficult to effectively improve the magnetic anisotropy and mechanical properties.

  The magnetic metal particles may be either polycrystalline or single crystal, but are more preferably single crystal. When core-shell magnetic particles containing single-crystal magnetic metal particles are integrated into a magnetic body, the easy axis of magnetization can be aligned and the magnetic anisotropy can be controlled. High frequency characteristics can be improved as compared with a magnetic material containing core-shell magnetic particles containing metal particles.

  The magnetic metal particles preferably have an average particle size of 1 nm to 1000 nm, preferably 1 nm to 100 nm, and more preferably 10 nm to 50 nm. If the average particle size is less than 10 nm, superparamagnetism may occur and the amount of magnetic flux may decrease. On the other hand, if the average particle size exceeds 1000 nm, eddy current loss increases in the high frequency region, and the magnetic characteristics in the intended high frequency region may be degraded.

  In core-shell magnetic particles, magnetic metal particles having a multi-domain structure are more energetically stable than those having a single-domain structure. The core-shell type magnetic particles including magnetic metal particles having a multi-domain structure have lower permeability high frequency characteristics than those having magnetic domain particles having a single magnetic domain structure. For this reason, when the core-shell magnetic particles are used as a high-frequency magnetic member, it is preferable that the core-shell magnetic particles exist as magnetic metal particles having a single magnetic domain structure.

  Since the limit particle size of the magnetic metal particles that maintain the single magnetic domain structure is about 50 nm or less, the average particle size of the magnetic metal particles is preferably 50 nm or less. From the above points, it is desirable that the magnetic metal particles have an average particle diameter of 1 nm to 1000 nm, preferably 1 nm to 100 nm, and more preferably 10 nm to 50 nm.

  The magnetic metal particles may be spherical, but are preferably flat or rod-shaped having a large aspect ratio (for example, 10 or more). The rod shape includes a spheroid. Here, “aspect ratio” refers to the ratio of height to diameter (height / diameter). In the case of a spherical shape, the aspect ratio is 1 because the height is also equal to the diameter. The aspect ratio of the flat particles is (diameter / height). The aspect ratio of the bar is (bar length / bar bottom diameter). However, the aspect ratio of the spheroid is (major axis / minor axis). When the aspect ratio is increased, magnetic anisotropy depending on the shape can be imparted, and the high frequency characteristics of the magnetic permeability can be improved. In addition, when a desired member is produced by integrating the core-shell magnetic particles, it can be easily oriented by a magnetic field, and the high-frequency characteristics of magnetic permeability can be improved. Further, by increasing the aspect ratio, it is possible to increase the critical particle diameter of magnetic metal particles having a single magnetic domain structure, for example, a particle diameter exceeding 50 nm.

  In the case of a spherical magnetic metal particle, the critical particle size for forming a single domain structure is about 50 nm. The flat magnetic metal particles having a large aspect ratio can increase the critical particle size, and the high frequency characteristics of the magnetic permeability do not deteriorate. In general, particles having a larger particle size are easier to synthesize, and therefore, a larger aspect ratio is advantageous from the viewpoint of production. Furthermore, by increasing the aspect ratio, the core-shell type magnetic particles having magnetic metal particles can be integrated to produce a desired member, so that the filling rate can be increased. The magnetization can be increased, and as a result, the magnetic permeability can be increased.

  The oxide coating layer covering the surface of the magnetic metal particle is made of an oxide containing at least one nonmagnetic metal that is one of the constituent components of the magnetic metal particle. This oxide coating layer not only improves the oxidation resistance of the internal magnetic metal particles, but also integrates the core-shell magnetic particles covered with the oxide coating layer to produce the desired magnetic material. The particles can be electrically separated to increase the electrical resistance of the member. By increasing the electrical resistance of the member, it is possible to suppress eddy current loss at high frequencies and improve the high-frequency characteristics of magnetic permeability. For this reason, it is preferable that an oxide coating layer is electrically high resistance, for example, it is preferable to have a resistance value of 1 mΩ · cm or more.

  In the core-shell magnetic particles according to the embodiment described above, a magnetic metal containing at least one selected from the group consisting of Fe, Co, Ni, a nonmagnetic metal, and at least one element selected from carbon and nitrogen The magnetic metal particle containing has a high saturation magnetization, and the oxide coating layer made of an oxide containing at least one nonmagnetic metal that is one of the components of the magnetic metal particle coated on the surface of the magnetic metal particle is High insulation. By covering the surface of magnetic metal particles with high saturation magnetization with a highly insulating oxide coating layer, eddy current loss that causes loss at high frequencies can be suppressed, and core-shell type magnetism with a high anisotropic magnetic field Particles can be obtained.

  Such a magnetic material containing core-shell magnetic particles can control the permeability, that is, the permeability real part (μ ′) and the permeability imaginary part (μ ″) in a high frequency range from 100 MHz to GHz. In particular, the magnetic material has almost no loss other than ferromagnetic resonance loss and has high magnetic permeability at high frequency. And has a ferromagnetic resonance frequency in the range of several GHz.Therefore, in the frequency band lower than the ferromagnetic resonance frequency, a high permeability real part (μ ′) and a low permeability imaginary part (μ ″) are exhibited. And can be effectively used as a high permeability component inserted in the space between the finite ground plane.

  The composition analysis of magnetic metal particles can be performed, for example, by the following method. For example, the analysis of a nonmagnetic metal such as Al can include ICP emission analysis, TEM-EDX, XPS, SIMS and the like. According to the ICP emission analysis, the magnetic metal particle (core) portion dissolved by weak acid, the residue dissolved by alkali or strong acid (oxide shell), and the analysis result of the whole particle are compared. The composition of the metal particles can be confirmed, that is, the amount of nonmagnetic metal in the magnetic metal particles can be measured. In addition, according to TEM-EDX, the general composition of magnetic metal particles can be confirmed by squeezing the beam onto magnetic metal particles (core) and shell, irradiating EDX, and semi-quantifying. Furthermore, according to XPS, the bonding state of each element constituting the magnetic metal particle can be examined. For example, an element such as carbon is difficult to dissolve in the shell portion, so it is considered that the element is dissolved in the core, which is the magnetic metal particle, and the composition of the entire magnetic metal particle is analyzed by ICP emission analysis. Can be measured. By such a composition analysis of the magnetic metal particles, a trace amount of nonmagnetic metals such as Al and elements such as carbon can be measured in the magnetic metal particles.

  In addition, in the core-shell type magnetic particle and the magnetic body using the same according to the present embodiment, the material structure is SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), and the diffraction pattern (including solid solution confirmation) is TEM. Diffraction, XRD (X-ray Diffraction), and identification and quantitative analysis of constituent elements are ICP (Inductively coupled plasma) emission analysis, X-ray fluorescence analysis, EPMA (Electron Probe Micro-Analysis), EDX (Energy X-ray energy analysis). Spectrometer), SIMS (Secondary Ion Mass Spe In Trometry) or the like, can be respectively discriminated (analysis). The average particle diameter of the magnetic metal particles can be obtained from the average of a large number of particle diameters by averaging the longest diagonal line and the shortest diagonal line of each particle by TEM observation and SEM observation. It is.

  Hereinafter, an experimental example of the core-shell magnetic particles of the present embodiment and a magnetic body using the same will be described in more detail in comparison with a comparative experimental example. The average crystal grain size of the magnetic metal particles in the following experimental examples and comparative experimental examples was measured based on TEM observation. Specifically, an average of the longest diagonal line and the shortest diagonal line of each particle projected by TEM observation (photograph) was used as the particle diameter, and the average was obtained. In the photograph, three or more unit areas of 10 μm × 10 μm were taken and the average value was obtained. The composition analysis of the microstructure was performed based on EDX analysis.

(Experimental example 1)
Argon was introduced at 40 L / min as a plasma generating gas into the chamber of the high frequency induction thermal plasma apparatus to generate plasma. The plasma in this chamber is injected with raw material Fe powder with an average particle size of 10 μm and Al powder with an average particle size of 3 μm at 3 L / min together with argon (carrier gas) so that Fe: Al is 20: 1 by weight ratio. did. At the same time, acetylene gas was introduced into the chamber as a carbon coating material together with a carrier gas to obtain nanoparticles in which FeAl alloy particles were coated with carbon. The carbon-coated FeAl nanoparticles were reduced at 650 ° C. under a hydrogen flow of 500 mL / min, cooled to room temperature, and then taken out in an atmosphere of argon containing 0.1% by volume of oxygen to oxidize, Core-shell magnetic particles were produced.

  The obtained core-shell type magnetic particles had a structure in which the average particle diameter of the core magnetic metal particles was 32 nm and the thickness of the oxide coating layer was 4 nm. The magnetic metal particle of the core was composed of Fe—Al—C, and the composition ratio was Fe: Al: C = 81: 3: 7 in atomic ratio. The oxide coating layer was composed of Fe—Al—O. Such core-shell type magnetic particles and polyvinyl butyral resin were mixed at a weight ratio of 100: 30 and thickened to obtain a magnetic material.

  When the magnetic permeability and dielectric constant of the obtained magnetic material were evaluated, the magnetic permeability real part of the magnetic material was 2.2 (permeability imaginary part is 0.022 or less) and the dielectric constant real part was 3 (dielectric) at 1 GHz. The imaginary part was 0.03 or less.

(Experimental example 2)
Argon was introduced at 40 L / min as a plasma generating gas into the chamber of the high frequency induction thermal plasma apparatus to generate plasma. The plasma in this chamber is made of Fe powder having an average particle diameter of 10 μm, Co particles having an average particle diameter of 10 μm, and Al powder having an average particle diameter of 3 μm as Fe: Co: Al in an atomic ratio of 70:30:10. Injected with argon (carrier gas) at 3 L / min. At the same time, acetylene gas was introduced into the chamber as a carbon coating material together with a carrier gas to obtain nanoparticles in which FeCoAl alloy particles were coated with carbon. The carbon-coated FeCoAl nanoparticles were reduced at 600 ° C. under a hydrogen flow of 500 mL / min, cooled to room temperature, then taken out in an oxygen-containing atmosphere and oxidized to produce core-shell magnetic particles.

  The obtained core-shell type magnetic particles had a structure in which the average particle diameter of the core magnetic metal particles was 18 nm and the thickness of the oxide coating layer was 2.5 nm. The magnetic metal particles of the core were composed of Fe—Co—Al—C, and the composition ratio was Fe: Co: Al: C = 70: 30: 0.02: 0.02 in atomic ratio. The oxide coating layer was composed of Fe—Co—Al—O. Such core-shell type magnetic particles and polyvinyl butyral resin were mixed at a weight ratio of 100: 30 and thickened to obtain a magnetic material.

  When the magnetic permeability and dielectric constant of the obtained magnetic material were evaluated, the magnetic permeability real part was 3 (permeability imaginary part is 0.03 or less) and the dielectric constant real part was 2.5 (dielectric constant imaginary part) at 1 GHz. 0.025 or less).

(Comparative Experimental Example 1)
The plasma in the chamber of the high-frequency induction thermal plasma apparatus is composed of Fe powder having an average particle diameter of 10 μm and Al powder having an average particle diameter of 3 μm as raw materials together with argon (carrier gas) so that Fe: Al is 20: 1 by weight. Core-shell type magnetic particles were produced in the same manner as in Example 1 except that injection was performed at 3 L / min and no acetylene gas for carbonization was introduced.

  The obtained core-shell magnetic particles had a structure in which the average particle diameter of the core magnetic metal particles was 40 nm and the thickness of the oxide coating layer was 5 nm. The core magnetic metal particles were composed of Fe—Al, and the oxide coating layer was composed of Fe—O. In the magnetic metal particles of the core, Al segregated and the composition varied. Such core-shell type magnetic particles and polyvinyl butyral resin were mixed at a weight ratio of 100: 30 and thickened to obtain a magnetic material.

When the magnetic permeability and dielectric constant of the obtained magnetic material were evaluated, the magnetic permeability decreased from several hundred MHz to about 1 at 1 GHz, and the magnetic permeability was the same as that of air. This low magnetic property is due to the fact that the oxide coating layer of the core-shell particles of Comparative Example 1 is insufficient to provide the insulating properties of the material. In the core-shell particles having an insufficient oxide coating layer, the individual magnetic metal particles are electrically connected to each other, and eddy current loss occurs at a high frequency. As a result, the permeability decreases in the 1 GHz band, and the material is a magnetic substance. It is thought that it has disappeared.
In addition, this magnetic material has a low resistance and could not be evaluated for accurate dielectric properties.

  As described above, it has been found that the magnetic materials of Experimental Examples 1 and 2 have superior magnetic characteristics and dielectric properties as compared with the magnetic material of Comparative Experimental Example 1.

(Second Embodiment)
The antenna device of this embodiment is the same as that of the first embodiment except that the antenna has a structure in which power is supplied using a coaxial line. Accordingly, the description overlapping with the first embodiment is omitted.

  FIG. 6 is a cross-sectional view showing the configuration of the antenna device of the present embodiment. The antenna device includes a finite ground plane 10, a rectangular conductor plate 12 provided above the finite ground plane 10, an antenna 14 disposed substantially parallel to the finite ground plane 10 above the finite ground plane 10, and the finite ground plane 10 and the antenna 14. And a magnetic body 16 provided in at least a part of the space.

  Both the finite ground plane 10 and the rectangular conductor plate 12 are made of a conductive material. One side of the rectangular conductor plate 12 is connected to the finite ground plane 10 and is electrically short-circuited. And the bending part 18 substantially parallel to this one side is provided. The antenna 14 is provided on the rectangular conductor plate 12, and the antenna 14 extends in a substantially vertical direction on one side where the rectangular conductor plate 12 is in contact with the finite ground plane 10. The feeding point 22 of the antenna 14 is located in the vicinity of the side facing the one side of the rectangular conductor plate 12. In FIG. 6, the antenna 14 is a dipole antenna.

  Further, this antenna device has a coaxial line 20. The coaxial line 20 includes an inner conductor 20a made of a linear conductor and an outer conductor 20b made of a conductor that surrounds the side surface of the inner conductor 20a in a cylindrical shape. The inner conductor 20 a is connected to the feeding point 22, and the outer conductor of the coaxial line 20 is short-circuited to the finite ground plane 10 immediately below the feeding point 22.

  According to the above-described embodiment, impedance matching can be achieved even when the antenna device is in a low posture, and a wide band characteristic can be obtained. And the leakage current to the coaxial line 20 which is a feeder can be suppressed. This is because the rectangular conductor plate 10 serves as a balance-unbalance converter called a balun. Therefore, it is possible to suppress the leakage current to the coaxial line 20 at the same time as the antenna matching and the broadband characteristic.

(Third embodiment)
The antenna device of the present embodiment is the same as that of the first embodiment except that the rectangular conductor plate and the antenna are arranged on substantially the same plane and the rectangular conductor plate has a cut portion for arranging the antenna. It is. Accordingly, the description overlapping with the first embodiment is omitted.

  FIG. 7 is a perspective view showing the configuration of the antenna device of the present embodiment. As shown in the figure, the antenna 14 is disposed on substantially the same plane as the portion of the rectangular conductor plate 12 parallel to the finite ground plane 10. And in order to be able to arrange | position the antenna 14 in the same plane as the part parallel to the finite ground plane 10 of the rectangular conductor board 12, the part (notch) cut into the rectangular conductor board 12 so that a short circuit with the antenna 14 may be avoided. 24.

  With the above configuration, as in the first embodiment, antenna matching in a low posture and broadband characteristics thereof can be obtained, and at the same time, the rectangular conductor plate 12 and the antenna 14 can be configured on the same plane. Therefore, it is possible to further reduce the posture and facilitate mounting.

(Fourth embodiment)
The antenna device of the present embodiment penetrates through a finite ground plane, a magnetic body above the finite ground plane, a rectangular conductor board above the magnetic body, and the magnetic body, and connects the vicinity of one side of the rectangular conductor plate to the finite ground plane. An electric conductor and an antenna disposed substantially parallel to the finite ground plane above the finite ground plane, extending in a substantially vertical direction to the one side, and having a feeding point located in the vicinity of the side facing the one side of the rectangular conductor plate Have. Here, the upper direction is an expression for showing the positional relationship with other elements based on the case where the finite ground plane is below, and is always above the vertical direction. It is not a representation. Further, the term “above” includes a case where two elements are in contact with each other. This embodiment is the same as the first embodiment except that a rectangular conductor plate and a through hole are used instead of the rectangular conductor plate having a bent portion. Accordingly, the description overlapping with the first embodiment is omitted.

  FIG. 8 is a perspective view showing the configuration of the antenna device of the present embodiment. This antenna device includes a finite ground plane 10, a magnetic body 16 above the finite ground plane 10, and a rectangular conductor plate 12 on a flat plate above the magnetic body 16. A plurality of conductors that penetrate the magnetic body 16 and physically and electrically connect the vicinity of one side of the rectangular conductor plate 12 to the finite ground plane 10 are provided. This conductor is a through hole 30 in which holes are formed in the rectangular conductor plate 12 and the magnetic body 16 and then electrically connected by plating. In addition, the antenna 14 is disposed above the finite ground plane 10 so as to be substantially parallel to the finite ground plane 10 and extends in a substantially vertical direction to one side of the rectangular conductor plate 12 in which the through hole 30 is provided. The feeding point 22 of the antenna device is located on the other side of the rectangular conductor plate 12 facing the one side, that is, in the vicinity of the side farthest from the side where the rectangular conductor plate 12 is short-circuited to the finite ground plane 10 by the through hole 30. .

  Here, the fact that the through hole 30 is in the vicinity of one side of the rectangular conductor plate 12 means that the distance from one side to the through hole 30 is more than the distance from the other side facing the one side to the through hole 30. Say close.

  The combined structure of the rectangular conductor plate 12 and the through hole 30 of the antenna device of FIG. 8 is electrically the same as the rectangular conductor plate 12 having a bent portion in the first embodiment. Further, in the present embodiment, the magnetic body 16 realizes miniaturization and widening of the antenna device by shortening the wavelength, and also functions as a mechanical structure support member. The magnetic body 16 may be a magnetic body alone or may be a laminated magnetic body of a magnetic layer and a nonmagnetic dielectric layer. In the case of a stacked structure, it is desirable to select a combination in which the refractive index of the magnetic layer and the refractive index of the nonmagnetic dielectric layer are substantially the same because unnecessary radio wave reflection can be suppressed.

  With the above configuration, in the antenna device of the present embodiment, as in the first embodiment, impedance matching can be achieved even when the antenna device is downsized including a low profile, and broadband characteristics can be obtained. it can. Further, by connecting the rectangular conductor plate and the finite ground plane through the through hole, a configuration that is electrically equivalent to that of the first embodiment can be realized by using a conventional and inexpensive printed circuit board processing technique. There is also an advantage that.

(Fifth embodiment)
In the antenna device according to the present embodiment, in the fourth embodiment, the magnetic body includes a first magnetic body layer between the finite ground plane and the rectangular conductor plate, and a second magnetic body above the rectangular conductor plate. It consists of layers. An antenna is provided above the second magnetic layer. The antenna is formed as a strip line. Except for these points, the fourth embodiment is basically the same as the fourth embodiment, so that the description overlapping with the fourth embodiment is omitted.

  FIG. 9 is a perspective view showing the configuration of the antenna device of the present embodiment. In the present embodiment, the magnetic body includes a first magnetic layer 16a between the finite ground plane 10 and the rectangular conductor plate 12, and a second magnetic layer 16b between the rectangular conductor plate 12 and the antenna 14. It has a two-layer structure. The first magnetic layer 16a and the second magnetic layer 16b may be a magnetic material alone, or may be a laminated magnetic material of a magnetic material layer and a nonmagnetic dielectric layer. In the case of a laminated structure, it is desirable to select a combination in which the refractive index of the magnetic layer and the refractive index of the nonmagnetic dielectric layer are substantially the same because unnecessary radio wave reflection can be suppressed. This is the same as the fourth embodiment.

  The antenna 14 is formed as a strip line on the second magnetic layer 16b. The rectangular conductor plate 12 provided between the first magnetic layer 16a and the second magnetic layer 16b can be formed by a general multilayer substrate processing technique.

  With the above configuration, in the antenna device of the present embodiment, as in the fourth embodiment, impedance matching can be achieved even when the antenna device is downsized including low profile, and a wideband characteristic can be obtained. it can. Further, by forming the antenna 14 as a strip line on the second magnetic layer 16b, the antenna device can be manufactured easily and inexpensively.

  Further, here, the case where the antenna is a strip line with a structure of a magnetic material having a two-layer structure is described. Similarly to the third embodiment, the rectangular conductor plate 12 is provided with a cut portion (notch), and the antenna 14 is provided as a strip line on the first magnetic layer 16a, so that the magnetic body is made into one layer. Accordingly, it is possible to further reduce the size of the antenna device.

(Sixth embodiment)
The antenna device according to the present embodiment is provided with a finite ground plane and an upper portion of the finite ground plane, one end of which is connected on a predetermined straight line of the finite ground plane, bends at a substantially right angle, and has a bent portion substantially parallel to the previous straight line. Provided, the other end is disposed substantially parallel to the finite ground plane above the finite ground plane, extending in a direction substantially perpendicular to the previous straight line, and the feeding point is a comb-shaped linear shape. An antenna located near the other end of the conductor, and a magnetic body provided in at least a part of the space between the finite ground plane and the antenna.

  The antenna device of the present embodiment is the same as that of the first embodiment except that a comb-shaped linear conductor having a bent portion is used instead of the rectangular conductor plate having the bent portion of the first embodiment. is there. Accordingly, the description overlapping with the first embodiment is omitted.

  FIG. 10 is a perspective view showing the configuration of the antenna device of the present embodiment. As shown in the figure, the antenna device of the present embodiment includes a finite ground plane 10, a comb-shaped linear conductor 12 provided above the finite ground plane 10, and an antenna 14. And it has the magnetic body 16 provided in the at least one part space between the finite ground plane 10 and the antenna 14. FIG.

  Here, the comb-shaped linear conductor 12 is a linear conductor having a shape in which a plurality of linear conductors are connected to each other at one end, that is, a comb shape for combing hair. One end having a comb shape is physically and electrically connected to the finite ground plane 10 on a predetermined straight line of the finite ground plane 10. The comb-shaped linear conductor 12 includes a bent portion 18 that is bent substantially at a right angle and substantially parallel to the previous straight line. Further, the comb-shaped linear conductor 12 is not connected to the other end, that is, the finite ground plane 10, and the end where the plurality of linear conductors are connected to each other is substantially the same as the straight line and the bent portion 18. It has a parallel shape. The antenna 14 extends in a direction substantially perpendicular to the previous straight line, and the feeding point 22 is located near the other end of the comb-shaped linear conductor 12.

  With the above configuration, antenna matching in a low posture and its wideband characteristics can be obtained as in the first embodiment. Furthermore, it is possible to further reduce the frequency at which antenna matching can be achieved. The reason for this is that according to the structure of the present embodiment, the gap between the parallel conductors of the combs causes slight leakage of the electric field of the electromagnetic wave propagating between the comb-shaped linear conductor 12 and the finite ground plane 10. Allow. However, since the length of the gap in the longitudinal direction is shorter than the half wavelength of the electromagnetic wave, no electromagnetic wave is emitted. Therefore, even if the length of the conductor is the same, the propagation wavelength of the electromagnetic wave under the comb-shaped linear conductor 12 is longer than the propagation wavelength of the electromagnetic wave under the rectangular conductor plate in the first embodiment. It is because it can do.

(Seventh embodiment)
In the antenna device according to the present embodiment, the comb-shaped linear conductor has a linear portion that is substantially perpendicular to the finite ground plane and a linear portion that is substantially parallel to the finite ground plane with the bent portion interposed therebetween. The part is the same as in the sixth embodiment except that the part has a meander shape. Therefore, the description overlapping with the sixth embodiment is omitted.

  FIG. 11 is a perspective view showing the configuration of the antenna device of the present embodiment. As shown in the figure, the antenna device of the present embodiment has comb-shaped linear conductors 12 as in the antenna device of FIG. The comb-shaped linear conductor 12 includes a linear portion substantially perpendicular to the finite ground plane 10 on the side connected to the finite ground plane 10 and a linear portion substantially parallel to the finite ground plane 10 with the bent portion 18 interposed therebetween. Have. A linear portion substantially parallel to the finite ground plane 10 has a meander shape.

  With the above configuration, antenna matching in a low posture and its wideband characteristics can be obtained as in the seventh embodiment. Furthermore, it is possible to further reduce the frequency at which antenna matching can be achieved. This is because, according to the structure of the present embodiment, the electromagnetic wave propagation under the meandering comb-shaped linear conductor 12 is affected by the current flowing through the meander-shaped comb-shaped linear conductor 12, and is reduced by the current. This is because the frequency effect occurs.

  Here, the comb-shaped linear conductor 12 and the antenna 14 may be arranged on substantially the same plane, and a cut portion for arranging the antenna 14 may be provided in the comb-shaped linear conductor 12 to further reduce the size. Is possible.

(Eighth embodiment)
The antenna device of this embodiment is the same as that of the first embodiment except that a plurality of notches are provided on a side of a rectangular conductor plate that is perpendicular to one side connected to a finite ground plane. Accordingly, the description overlapping with the first embodiment is omitted.

  FIG. 12 is a perspective view showing the configuration of the antenna device of the present embodiment. Unlike the antenna device of FIG. 1, a plurality of notches 32 are provided on a side of the rectangular conductor plate 12 perpendicular to one side connected to the finite ground plane 10.

  With the above configuration, antenna matching in a low posture and its wideband characteristics can be obtained as in the first embodiment. Furthermore, it is possible to further reduce the frequency at which antenna matching can be achieved. This is because, according to the structure of the present embodiment, the propagation of electromagnetic waves under the notched rectangular conductor plate 12 is affected by the current flowing on the notched rectangular conductor plate 12, and the effect of lowering the frequency due to this current is obtained. This is because it happens.

  The embodiments of the present invention have been described above with reference to specific examples. The above embodiment is merely given as an example, and does not limit the present invention. In the description of the embodiment, the description of the antenna device etc. that is not directly required for the explanation of the present invention is omitted, but the elements related to the required antenna device etc. are appropriately selected and used. be able to.

  In addition, all antenna devices that include the elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention. The scope of the present invention is defined by the appended claims and equivalents thereof.

It is a block diagram of the antenna apparatus of 1st Embodiment. It is a block diagram of the 1st modification of the antenna device of 1st Embodiment. It is a block diagram of the 2nd modification of the antenna device of 1st Embodiment. It is explanatory drawing of the principle of operation of the antenna device of 1st Embodiment. It is sectional drawing of the antenna apparatus at the time of using a monopole antenna in 1st Embodiment. It is sectional drawing which shows the block diagram of the antenna apparatus of 2nd Embodiment. It is a perspective view which shows the structure of the antenna device of 3rd Embodiment. It is a perspective view which shows the structure of the antenna device of 4th Embodiment. It is a perspective view which shows the structure of the antenna device of 5th Embodiment. It is a perspective view which shows the structure of the antenna device of 6th Embodiment. It is a perspective view which shows the structure of the antenna apparatus of 7th Embodiment. It is a perspective view which shows the structure of the antenna apparatus of 8th Embodiment.

Explanation of symbols

10 finite ground plane 12 rectangular conductor plate, comb-shaped linear conductor 14 antenna 16 magnetic body 16a first magnetic body layer 16b second magnetic body layer 18 bent portion 20 coaxial line 22 feeding point 24 notch (notch)
30 through hole 32 notch

Claims (17)

With a finite ground plane,
A rectangular conductor plate provided above the finite ground plane, having one side connected to the finite ground plane and having a bent portion substantially parallel to the one side;
An antenna which is disposed substantially parallel to the finite ground plane above the finite ground plane, extends in a direction substantially perpendicular to the one side, and a feeding point is located in the vicinity of the other side facing the one side of the rectangular conductor plate;
A magnetic body provided in at least a part of the space between the finite ground plane and the antenna;
I have a,
The magnetic body is
Magnetic metal containing at least one selected from the group consisting of Fe, Co, Ni, and selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr Magnetic metal particles containing at least one non-magnetic metal and at least one element selected from carbon (C) and nitrogen (N), and a component of the magnetic metal particles coated on the surface of the magnetic metal particles Core-shell magnetic particles comprising an oxide coating layer made of an oxide containing at least one nonmagnetic metal that is one of the following:
Insulating material of resin or inorganic material provided with voids, in which the core-shell magnetic particles are dispersed;
Antenna apparatus characterized by have a. With a finite ground plane,
A magnetic body above the finite ground plane;
A rectangular conductor plate above the magnetic body;
A conductor that penetrates the magnetic body and connects one side of the rectangular conductor plate to the finite ground plane; and
An antenna which is disposed substantially parallel to the finite ground plane above the finite ground plane, extends in a direction substantially perpendicular to the one side, and a feeding point is located in the vicinity of the other side facing the one side of the rectangular conductor plate;
I have a,
The magnetic body is
Magnetic metal containing at least one selected from the group consisting of Fe, Co, Ni, and selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr Magnetic metal particles containing at least one non-magnetic metal and at least one element selected from carbon (C) and nitrogen (N), and a component of the magnetic metal particles coated on the surface of the magnetic metal particles Core-shell magnetic particles comprising an oxide coating layer made of an oxide containing at least one nonmagnetic metal that is one of the following:
Insulating material of resin or inorganic material provided with voids, in which the core-shell magnetic particles are dispersed;
Antenna apparatus characterized by have a. With a finite ground plane,
A comb shape provided above the finite ground plane, having one end connected on a predetermined straight line of the finite ground plane, bent at a substantially right angle, provided with a bent portion substantially parallel to the straight line, and the other end substantially parallel to the straight line A linear conductor;
An antenna that is disposed substantially parallel to the finite ground plane above the finite ground plane, extends in a direction substantially perpendicular to the straight line, and a feeding point is located near the other end of the comb-shaped linear conductor;
A magnetic body provided in at least a part of the space between the finite ground plane and the antenna;
I have a,
The magnetic body is
Magnetic metal containing at least one selected from the group consisting of Fe, Co, Ni, and selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr Magnetic metal particles containing at least one non-magnetic metal and at least one element selected from carbon (C) and nitrogen (N), and a component of the magnetic metal particles coated on the surface of the magnetic metal particles Core-shell magnetic particles comprising an oxide coating layer made of an oxide containing at least one nonmagnetic metal that is one of the following:
Insulating material of resin or inorganic material provided with voids, in which the core-shell magnetic particles are dispersed;
Antenna apparatus characterized by have a. The coaxial line is further connected to the feeding point, and the outer conductor of the coaxial line is connected to the finite ground plane immediately below the feeding point. 4. The antenna device according to any one of 3 .   The antenna device according to claim 1 or 2, wherein the rectangular conductor plate and the antenna are arranged on substantially the same plane, and the rectangular conductor plate has a cut portion for arranging the antenna. The magnetic body is a first magnetic layer between the finite ground plane and the rectangular conductor plate;
It is composed of a second magnetic layer above the rectangular conductor plate,
The antenna device according to claim 2, wherein the antenna is provided above the second magnetic layer.   The antenna device according to claim 1, wherein a plurality of notches are provided on a side perpendicular to the one side of the rectangular conductor plate. The comb-shaped linear conductor has a linear portion substantially perpendicular to the finite ground plane across the bent portion, and a linear portion substantially parallel to the finite ground plane,
4. The antenna device according to claim 3, wherein the substantially parallel linear portions are meandered.   4. The antenna device according to claim 3, wherein the comb-shaped linear conductor and the antenna are arranged on substantially the same plane, and the comb-shaped linear conductor has a cut portion for arranging the antenna. Furthermore, having a dielectric that occupies a space other than the space occupied by the magnetic body between the finite ground plane and the antenna,
4. The antenna device according to claim 1, wherein the dielectric body and the magnetic body have substantially the same refractive index. The magnetic metal particles, according to claim 1 to claim 3, characterized in that it contains the non-magnetic metal and 0.001 atomic% to 20 atomic% or less of the element 20 at% 0.001 atomic% or more The antenna device according to any one of claims. The magnetic metal particles include FeCo, Al, and carbon;
The oxide coating layer includes Al;
The FeCo contains Co at 10 atomic% to 50 atomic%, Al is 0.001 atomic% to 5 atomic% with respect to the FeCo, and the carbon is 0.001 atomic with respect to the FeCo. The antenna device according to claim 1 , wherein the antenna device is blended in an amount of not less than 5% and not more than 5 atomic%. The 70 vol% filling factor more than 10 vol% in the magnetic body of the core-shell type magnetic particles below the filling rate in the magnetic body of insulating material is equal to or less than 5 vol% or more 80 vol% claims 1 to Item 4. The antenna device according to any one of Items 3 to 4 . Said magnetic body, an antenna device according to any one claims 1 to 3, characterized in that a laminated magnetic material formed by the magnetic layer and the nonmagnetic dielectric layer. The magnetic permeability of the magnetic material is equal to or less than 10 greater than 1, the antenna device according to any one claims 1 to 3, characterized in that the dielectric constant of the magnetic body is 10 or less larger than 1. 16. The antenna device according to claim 15, wherein the magnetic material has a magnetic permeability greater than 1 and less than or equal to 5, and a magnetic permeability greater than a dielectric constant. 16. The antenna device according to claim 15, wherein the magnetic substance has a magnetic permeability greater than 1 and less than or equal to 5, and a dielectric constant greater than the magnetic permeability.

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